/ Glacier Glasses are Rubbish

Can anyone recommend a decent pair of cat 4 glacier glasses? I've got a pair of Julbo...Not sure which model exactly, I think they might be the Dolgan but they don't look exactly like the ones currently on the Julbo website.

Anyway they're shite. The arms dig into my head and the lenses get fogged up as soon as I get going. Any contenders? Julbo seem to have the market sewn up. There's also the Dragon Mountaineering X but I would've thought wrap-arounds would be a better design for glacier glasses than wayfarers.

In reply to Jim 1003:
Not sure if you're joking but I just picked up a pair of wedze wrap arounds for €15 cat 4 not polarised. Worked fine for me and I overheat easily. They don't have the soft padding that some do, they're really just wrap around plastic alpine sun glasses.

Sounds a really bad idea not to be polarised. With that degree of reduction in overall light transmitted, I would imagine that your pupils will be more dilated and you will get even more UV light arriving at your retina. Are you sure that they are not polarised? Does Cat 4 not include an obligatory polarisation?

Polarising is just a coating to cut out glare. It has nothing to do with the Category of the glasses. Polarized glasses are best used on water, there's no real benefit to polarized glasses for mountain use.

> Sounds a really bad idea not to be polarised. With that degree of reduction in overall light transmitted, I would imagine that your pupils will be more dilated and you will get even more UV light arriving at your retina. Are you sure that they are not polarised?

That doesn't make any sense. The effect of a polarized lens on radiation has nothing to do with the frequency of that radiation.

Bloc Chameleon X400 Cat 4's - they have metal wire running through the arm so you can change the shape to your ears and head. Also the nose pads are on a metal piece, again can be formed to your face. Lenses are already vented but the surround is removable if you need more venting. Should be less than £40 too.

I can see that generally, but I thought(and I realise that I may be wrong) that depending on the separation, that it could screen out certain wavelengths by affecting the phase of those particular wavelengths. Is that totally wrong?

Phase has also nothing to do with it; the only significant thing is the frequency of the radiation (or wavelength, if prefer to think about things that way, the two values being directly related by the equation (frequency)x(wavelength)=(speed of light).)

The 'Cat 4' rating indicates a particular range of transmittance for light in the visible spectrum only.

Polarized lenses are helpful in reducing 'glare' (since light which is reflected off water becomes strongly polarized in one direction, so can therefore be selectively filtered out) but otherwise aren't relevant in this discussion.

But it is because they selectively screen out the reflection coming up off the snow in the same way they screen it coming off the water.

To the OP: do you need them? I have bad eyes but have still only used normal sunglasses on glaciers and haven't had the burns. Top sunglass tip for me at the moment is to buy PPE sunglasses from a builders shop. £6 will get you some good looking bolle ones.

I've skied toured with polarised glasses and you sometimes can't tell when you're going to hit an icy patch as the lenses make all the snow look pretty much the same, not such a problem moving slowly on the flat or uphill but it is if you're turning when descending quickly.

> I am sure that on a plas y brenin course many moons ago it was suggested to try to have polarised lenses due to the reflected light, or does my memory serve me ill?

Sure - that's the point of polarized lenses. As discussed above, since light reflected from water can become strongly polarized in one direction, polarized lenses can selectively filter out that reflected light. But that's not germane to your original point (and in any case, as others have implied, it might not be a desirable effect on snow/ice.)

What he means is that polarised lenses attenuate the brightest light (reflected glare) without attenuating everything else. With non-polarised glasses the lens needs to be darker to deal with the same amount of glare. Because the non-polarised lens is darker your pupils are likely to widen to try to see less bright objects, and thus let in more UV light.

It's actually a benefit to be able to see icy patches more clearly a lot of the time. A non polarized cat 4 lense or even a photochromatic lense that darkens to cat 4 is going to provide all the protection your eyes need. There is no real benefit to polarized lenses for mountain use.